In the semiconductor wafer fabrication process, it is common to use a chemical-mechanical polishing (CMP) process for achieving the object of planarization of the surface of wafer, in which a polishing pad fixed to a rotary table is used to contact with and polish the wafer. Fragments generated by polishing, and polishing slurry may be accumulated in voids of the polishing pad, and the polishing pad is then consumed so as to reduce the polishing effect over a long period. Therefore, it is common to use a conditioner for the removal of the fragments and polishing shiny remained in the polishing pad.
The conventional CMP abrasive pad conditioner is roughly classified into two categories: one is a diamond particle used as polishing material, and the other is a diamond film, deposited by chemical vapor deposition (CVD), used as polishing material.
In conventional technology, in respect of the CMP abrasive pad conditioner utilizing the diamond film deposited by CVD as polishing material, a CMP pad conditioner, provided by Taiwan Patent Publication No. 200948533, for example, is allowed to apply a CVD diamond coating onto a substrate consisting of ceramic material and an preferably unreacted carbide-forming material, while the conditioner thereof is provided with predictable or unpredictable raised surface features for assisting in the usefulness of the conditioner. The above raised surface features include concentric circles, broken or staggered concentric circles, spirals, broken spirals, rectangles, broken rectangles and so on.
In addition, the applicant provided, in Taiwan Patent Application No. 105124293 proposed previously, a CMP abrasive pad conditioner comprising a bottom substrate, an intermediate substrate and a polishing layer. The intermediate substrate is located on the bottom substrate. The intermediate substrate includes a hollow portion, an annular portion surrounding the hollow portion, and at least one projecting ring projecting out of the annular portion away from the bottom substrate. The projecting ring includes a plurality of bumps arranged to be spaced apart from each other along an annulus region. The bumps are extended in a radial direction of the intermediate substrate. Moreover, a diamond layer is located on the intermediate substrate, for conforming to the bumps, so as to form a plurality of the abrasive projections. The abrasive projections may be provided with either a flat top surface, or a rough top surface.
Furthermore, Taiwan Patent Publication No. 201249595, for example, provided a chemical mechanical planarization polishing pad conditioner, including a substrate comprising a first subset of protrusions and a second subset of protrusions, the first subset of protrusions comprising a first average height, and the second subset of protrusions comprising a second average height different from the first average height. Moreover, the top of the first subset of protrusions and that of the second subset of protrusions are both provided with a layer of polycrystalline diamond. In the specification of this application, it is mentioned that the distal surface of one or more protrusions of the first subset of protrusions may be provided with an irregular or rough surface, while the distal surface of each protrusion of the second subset of protrusions may be provided with irregular or rough surface. In another embodiment, however, the top of one or more projections of the first subset of protrusions may be provided with a flat surface, while the top of each protrusion of the second subset of protrusions may be provided with a flat surface.
The aforementioned CMP abrasive pad conditioner, using a CVD diamond film as polishing material, may be further combined with polishing particles. For instance, the applicant just disclosed, in Taiwan Patent Publication No. 201630689 proposed previously, a CMP abrasive pad conditioner comprising a base. The surface of the base is divided into a central surface and a peripheral surface concentrically. The central surface is depressed to be a depressed portion. The peripheral surface surrounding the central surface is depressed to form a plurality of mounting holes. Moreover, a plurality of sliders are provided on the peripheral surface and spread between the mounting holes. Each slider is provided with a conditioning face. In addition, the CMP conditioner is further provided with a plurality of conditioning posts, each conditioning post being correspondingly located in the mounting hole. The conditioning post comprises a post body and an abrasive material mounted on the top surface of the post body.
In the above prior art, for example, Taiwan Patent Publication No. 200948533 only mentioned the raised surface features formed on the substrate. Moreover, although Taiwan Patent Application No. 105124293, Taiwan Patent Publication No. 201249595 and No. 201630689 disclosed that the abrasive projection may be provided with a rough top surface, the rough top surface is not further defined or described yet. Only in the specification of Taiwan Patent Publication No. 201249595, it is roughly mentioned that roughness or the irregular surface may be at least partly attributable to roughness of porous graphite substrate of converted silicon carbide. Furthermore, the rough top surface is only one aspect of embodiment. In another embodiment, a flat top surface is also allowed. Obviously, the type of the top surface of the abrasive projection is not the key point on which the aforementioned prior art focused.
Therefore, even though the effects of consistent polishing or cutting speed, enhanced removing capability and etc., are obtained by providing a plurality of nonplanar bumps and arranging the bumps in a specific form via improvement on the top surface of the conventional CMP conditioner in the aforementioned prior art, the fragments remained in pores of the abrasive pad are still incapable of being removed effectively in the practical application of machining and the service life of the (MP conditioner is impacted.